The present invention relates generally to a dual mode switch for improved functioning in flashlight devices. More specifically, the present invention relates to an improved pushbutton switching mechanism for flashlights that provides a momentary and constant ON feature as well as a positive, reliable OFF position.
Flashlights of varying sizes and shapes are generally well known in the art. A number of such designs are known that utilize two or more batteries as their source for electrical energy. Typically, these batteries are carried in series in a tubular body, where the tubular body also serves as a handle for the flashlight. In order to operate the flashlight, an electrical circuit is established from one terminal of the battery, through a conductor to an external switch located in an opening in the side of the tubular body and then through another conductor to one contact of a bulb. After passing through the filament of the bulb, the electrical circuit emerges through a second contact of the bulb in electrical contact with a conductor, which in turn is in electrical contact with the flashlight housing. Finally, the flashlight housing provides an electrically conductive path to the other terminal at the rear of the battery. Actuation of the external switch completes the electrical circuit selectively enabling electrical current to pass through the filament of the bulb, thereby generating light that is then typically focused by a reflector to form a beam of light.
In general, the above described flashlight switch mechanisms operate in two basic manners. The first method of operation is a pushbutton type switch on the side or bottom of the light. The user depresses the switch, which has an internal mechanism that locks in the engaged position, turning the flashlight on. To turn the light off, the user again depresses the switch, unlocking it and turning the light off. This design has several drawbacks. One drawback is that the increased number of parts creates additional assembly steps and increases the difficulty of assembly process. Another drawback is that when a flashlight of this type is stored in luggage, it is susceptible to being compressed by items that may shift during transit, thereby activating the flashlight and draining the battery. A further drawback associated with this possibility of accidental activation is evident in high intensity flashlights that generate a great deal of heat during operation. If a flashlight of this type is tightly packed in luggage and accidentally activated, it may cause a fire.
In an attempt to resolve the drawbacks noted above, with respect to the pushbutton type switches, a second type of rotatable switch was developed for in-line use in flashlights. In one design, an end cap is rotatably secured to the flashlight body. To establish the required electrical contact, the end cap is rotated making contact between the rear contact of the batteries and the housing of the flashlight thereby energizing the circuit and illuminating the lamp bulb. A number of such prior art designs feature rotatable end caps which are rotated to move the batteries longitudinally within the flashlight body towards the lamp bulb, thereby causing contact between the battery contact and the base contact of the lamp bulb. In the open position, the battery is typically spring biased away from the base contact of the bulb. In other designs, miniature flashlights have been designed where the rotatable switch is located in the reflector end of the flashlight body. The lamp bulb is located within an insulated receptacle at the reflector end of the flashlight with one or more conductive pins being rotatably aligned by movement of the switch portion of the device to establish electrical contact. While these switch mechanisms are internal to the device and thus less subject to damage, they are overly complicated in design thereby requiring higher assembly tolerances, which result in making them more costly to manufacture.
There is therefore a need for a unique flashlight switching design that provides dual mode functionality with a reliable OFF position that has improved functionality over the designs of the prior art. There is a further need for a flashlight switch device that requires a reduced number of parts thereby simplifying assembly and manufacture while providing the necessary dual mode functionality described above.
In this regard, and in furtherance of the above stated objectives, the present invention provides a unique dual mode, inline switch mechanism that is fully integrated into the rear cap of a flashlight assembly to provide a completely self contained and waterproof switching mechanism. The switch assembly further provides a reliable OFF position that prevents the accidental activation of the light when the user desires that it remain off.
The flashlight of the present invention is constructed of primarily three sub assemblies including a flashlight head, a housing and an end cap. The entire basic structure of the switch of the present invention resides in the end cap of the flashlight assembly and includes an end cap structure that is designed to be rotatably attached to the end of a flashlight housing, a contact plate, a plunger and an elastomeric cover. Only the contact plate in the assembly of the present invention is required to be conductive. The end cap structure may be conductive so that its material is consistent with the material used in the outer housing of the flashlight however this is not required. The remaining components however are all electrically insulative and designed to properly isolate the conductive components to insure proper operation of the switch assembly. The plunger and contact plate are assembled and supported in an opening centrally located in the end cap. This provides for the plunger and contact plate to be located in a position at the rear of the flashlight where its motion is limited to a controlled and predictable linear travel. As can be seen, in this manner a switch assembly that operates in an in-line fashion is provided.
By limiting the travel of the plunger and contact plate to a predictable distance, the present invention can achieve the desired multifunctionality, namely, a momentary ON function, a full ON function and a verifiable OFF function. Each one of the functions is selected by rotating the end cap assembly including the switch of the present invention. As the end cap of the assembly is rotated, its linear spacing relative to the flashlight housing is increased or decreased thereby altering the mode of switch operation. In this manner an economical flashlight assembly is provided that has a reduced number of operational parts as compared to the prior art thereby producing a more reliable product.
The switch in the end cap further operates in conjunction with the spring element located in the head of the flashlight to further insure retention of the batteries and a positive electrical contact between the batteries and the head assembly. Further, the spring bias caused by the spring assembly in the head of the flashlight causes the batteries to be pressed rearwardly, which in turn causes the contact plate and plunger to be urged rearwardly creating the normally open bias for the switch assembly.
Accordingly, one of the objects of the present invention is the provision of a low cost flashlight having a superior dual mode switching mechanism. Another object of the present invention is the provision of a flashlight having a dual mode switching mechanism that includes a momentary ON, a full ON and a verifiable OFF position. A further object of the present invention is the provision of a flashlight having a dual mode switch that includes a reduced number of moving components thereby reducing manufacturing and assembly costs while improving the reliability of the assembly. Yet a further object of the present invention is the provision of a flashlight assembly having a dual mode switch that is integrated in an inline fashion and is waterproof.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.